Nonhalation photographic element



April 7, 1942. M. MARAsco 2,278,457

NON-HALATION. PHOTOGRAPHIC ELEMENTS FiledJuly 1:5, 19:59

fll/(a/i -50luble Resin +Hqher flli ohalic dcid Co ound INVENTOR.

Mal-Tin Mar 515cm.

ATTORNEY Patented Apr. 7, 1942 NONHALATION PHOTOGRAPHIC ELEMENT Martin Marasco, New Brunswick, N. 1., assignor to Du Pont Film Manufacturing Corporation, New York, N. Y., a corporation of Delaware Application July 13,

4 Claims.

This invention relates to anti-halation layers for photographic-elements. More particularly it relates to light sensitive photographic plate and film elements which bear a composite anti-halation backing comprising water-soluble antihalation layer and a protective layer therefor.

This invention has for an object the preparation of photographic elements which bear an anti-halation layer which may be readily removed in aqueous baths. A further object is the properation of anti-halation layers which do not form colored particles upon being mechanically stressed. A still further object is the production of anti-halation layers which are stable upon storage under humid conditions and do not deteriorate or'become tacky. A still further object is the preparation of photographic films which do not affect the sensitivity of photographic emulsion layers in contact therewith. Still other objects will appear hereinafter.

The above and other objects are accomplished according tothe following invention which comprises applying to a water-soluble anti-halation layer composed of a Water-soluble glue a protective layer consisting of an alkali soluble resin, said resin being not readily soluble in alkaline developers, having intimately dispersed therethrough a higher aliphatic acid or a water soluble salt thereof, having surface active properties. The higher aliphatic acids contain hydrocarbon radicals having at least 8 carbon atoms'which are attached to an acidic group, e. g. a carboxylic acid group, a sulfate group, a sulfonic acid groups, etc. The hydrocarbon radicals may contain substituents such as hydroxyl, halogen, e. g. chlorine, bromine, etc., alkoxy and alkyl groups.

By'alkali soluble resin is meant .aresin which is substantially insoluble in water at room temperature, butwhich is soluble in 5% alkali metal hydroxide solutions or solutions containing sufficient base to be equivalent thereto at room temperature.

The anti-halation layers may be composed of any water-soluble glue, e. g. albumin glue, bone glue, cartilageous glue, dextrines, fish glue, ising1as's,.tragacanth, etc., but are preferably composed of ordinary hide glue.

While fair results are obtained by the use of practically any'higher aliphatic mono acid or water-soluble salt thereof, better results are obtained by the use of higher aliphatic monocarboxylic acids and the water soluble salts thereof. The alkali metal salts of saturated primary aliphatic monocarboxylic acids of 12 to 18 carbon atoms are preferred.

1939, Serial No. 284,341

The above and other objects are accomplished according to a preferred embodiment hereof by the use of animal glue and a protective coating of an alkali soluble resin having uniformly disacid or a water-soluble salt thereof.

The alkali soluble resins used may be natural such as shellac, Sandarac, Amerol and colophony or artificial suchas the condensation products of an aldehyde, including aliphatic, aromatic and heterocyclic. aldehydes, particularly formaldehyde or a substance yielding formaldehyde with a phenol phenyl alkyl ether, phenylarylether, hy-

droxyarylcarboxylic acid.

The protective coating may be made by applying the material in' the form of an organic solvent solution containing the resin and the higher aliphatic acid or salt to the antihalation layer, The solutions may be made by dissolving the resin and acid or salt in a readily volatile solvent together or in separate solutions and subsequent mixing.

The solutions may be coated upon theback of the transparent plate or firm" support by any of the conventional methods, e. g. dipping, transfer or beading rollers, spraying, immersion beading, etc. In general a very thin layer upon the order of 0.5 to 3a is sufllcient for the purpose.

The invention will be further illustrated but 30 is not intended to be limited by the following examples in which the parts stated are parts by weight:

Example 1 Emarnple II Three parts of shellac were dissolved in'a solution consisting of 50 parts of, ethyl alcohol and 50 50 parts of ethyl acetate. This .was mixed with a a solution consisting of 3 parts of stearic acid dissolved in 50 parts of ethyl alcohol and 50 parts of ethyl acetate.

coated upon the back of a cellulose acetate film no bearing upon its front face a panchromatic persed therethrough a higher aliphatic carboxylic' The resulting solutionwas emulsion over an anti-halation layer composed of glue containing nigrosin.

The novel anti-halation elements are illustrated in the accompanying drawing wherein I is a transparent support or base, 2 is the light sensitive layer or emulsion layer, 3 is the antihalation layer composed of glue and an antihalation dye or pigment and 4 is a protective layer composed of an alkali soluble resin con-.

taining at least an equal amount of a higher aliphatic acid compound.

The base may be composed of any of the materials commonly used for such photographic materials. Thus, it may be made of glass, cellulose derivatives such as cellulose acetate, cellulose nitrate, cellulose-acetate-propionate, transparent resins, e. g. polyvinyl acetals, synthetic linear condensation products of high molecular weight, e. g. amides from 'dibasic acids and diamines, etc. The bases may be clear or have a permanent tint.

In general any dye which possesses the property of absorbing actinic light and being destroyed in ordinary photographic baths and which does not injure such baths may be used in the anti-halation layers.

The dye or pigment to be used in any specific instance is primarily determined by the light sensitivity of the emulsion. Such emulsions are usually gelatin silver halide emulsions which contain sensitizers such as cyanine, carbocyanine.

pseudo-cyanine, cyazine bases and salts. That is, it must be absorptive of light of the wave lengths to which the emulsion is sensitive. In general, the dye should be added in an amount sufiicient to give a photographic density of 0.8 or the amount of dyed layer should be sufiicient to give such a density. As examples of additional useful dyes and pigments, mention is made of:

. Metanil Yellow (C. I. 138) Titanium Ferrocyanid Prussian Blue Silver dithiazonate Mixtures of the dyes and/or pigments can be used, if desired. Thus various shades and colors, e. g. greens and blacks, can be formed.

In place of the particular acids described in the examples may be substituted various other pure or crude acids such as stearic, palmitic,. oleic, etc. acids or their water-soluble alkali metal ammonium or amine salts or mixtures of such compounds. Such products may be prepared in the usual manner by saponifying or hydrolyzing and neutralizing glycerides, etc., such as coconut oil,'palrn oil, olive oil, sardine oil, whale oil, linseed oil, stearin, tallow, cocoa butter, etc.

Practically any organic solvent which evaporates rapidly under moderate temperatures may be used. Suitable solvents include CCh trichloroethylene, acetone, monohydric alcohols of 1 to 5 carbon atoms, dioxane, benzene, toluene, etc.

This invention possesses the advantage that a nontacky anti-halation layer may be easily prepared.

A further advantage resides in the fact that the anti-halation film may be safely stored under conditions of high humidity without becoming tacky.

A major advantage of the use of the novel antihalation backings of this invention resides in the fact that they are readily dissolved in plain water. Thus, by washing before development one can prevent contamination of a developing bath and possible deleterious effect upon the film due to the introduction of foreign bodies. Certain dyes, e. g. auramine, reduce developer activity which is undesirable.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments hereof except as defined by the appended claims.

I claim:

l. A photographic element comprising a transparent support, an emulsion of'sensitized material upon one side thereof, an anti-halation layer upon the other side thereof composed of animal glue and a material absorptive of the rays to which the photographic coating is sensitized and .a protective coating superimposed upon said layer composed of an alkali soluble resin containing at least about an equal proportion of a material taken from the class consisting of higher aliphatic mono-carboxylic acids-and their water-- soluble salts.

2. A non-halation photographic element comprising a light-transmitting supporting layer, a photographically sensitive layer on one face thereof, an anti-halation layer composed of a water-soluble glue and an anti-halation dye upon the other face and a protective layer superimposed upon said anti-halation layer composed of an alkali soluble resin containing about an equal amount of a surface active substance taken from the class consisting of higher aliphatic mono- .carboxylic acids and their water soluble salts.

3. A photographic element comprising a transparent support, a light sensitive silver halide emulsion upon one side thereof, an anti-halation layer upon the other side thereof composed of animal glue and a material absorptive of the rays to which the photographic coating is sensitized and a protective coating for said layer composed of colophony containing about an equal proportion of an alkali metal salt of a higher aliphatic monocarboxylic acid.

4. A photographic element comprising a transparent support, a light sensitive silver halide emulsion upon one side thereof, an anti-halation layer upon the other side thereof composed of animal glue and a material absorptive of the rays to which the photographic coating is sensitized and a protective coating for said layer composed of shellac containing about an equal amount of a higher aliphatic primary aliphatic monocarboxylic acid.

MARTIN MARASCO. 

